Multiple switch-board



(N0 Modem 2 Sheets-Sheet l. T. J. PERRIN.

MULTIPLE SWITCH BOARD. No. 315,658. Patented Apr. 14, 1885.-

(N0 ModeL) 2 Sheets-Sheet 2. T. J. PERRIN.

MULTIPLE SWITCH BOARD.

WITNESSES R] Thoma 8 J ferrz'n,

By his %ney6 UNITED STATES -ATnNT Orrrcis.

THOMAS J. PERRIN. OF BROOKLYN, YORK, ASSIGNOR TO CHARLES P. HUNTINGTON,OF GREENVILLE, MISSISSIPPI.

MULTIPLE SWITCH-BOARD.

SPECIFICATION forming part of Letters Patent No. 315,658, dated April14, 1885.

Application filed November 4, 1884. (No model.)

To aZZ whont it may concern: 7

Be it known that I, THOMAS J. Pnnnnv, of Brooklyn, Kings county, NewYork, have invented certain new and useful Improvements in MultipleSwitch-Boards, of which the following is a specification.

The object of my invention is to improve the efficiency of operaton ofsuch boards and at the same time to reduce them to great sim- 10 plicityof structure.

In the accompanying drawings, Figure l is a diagram view illustratingportions of two sections, X and Y, of a multiple system of boards; andFig. 2 is a detail view, partly in section and diagram, showing a pairof corresponding terminals on the two sections of board.

In Fig. 1 I have shown on each board eight terminals merely, and willassume that the operator at X has charge of terminals from 1 to 4,inclusive, and that the operator at Y has charge of terminals 5 to 8,inclusive. Each line is equipped with an annunciator and a relay, asshown. The circuits, however, from the annunciators to the relays areomitted in this figure, as it will be difficult to properly illustratethem, and they are shown in complete detail in Fig. 2.

I have indicated two lines as connected on the boards-that is, line No.1, which is in special charge of the operator at X, and line No. 8,which is in charge of the operator at Y. As all the lines are similarlyconnected I and equipped, a description of one will be sufficient, andfurther illustration is therefore unnecessary. front and back plates, AB, between which at each line terminal a tubular electromagnetic coil,0, without a core, is secured. The front and back plates, A B, are boredthrough in line with the opening through the coil, as clearly shown inthe drawings; and in the face B of the board around each of saidopenings is set an annular metallic plate or ring, a, with which themain line is connected, as will be presently described. Suppose now thatin Fig. 2 the terminals illustrated are, say, No. 1 terminals on boardsX and Y. A circuit from a local battery, L B, one pole of which is Theboards are formed with grounded, passes from the battery through thecoil 0 at station X out of the coil to a contact, a, against which aspring contact, I), normally presses, from said springcontact throughthe coil of the magnet O at station Y, to the contact a and springcontact-arm b,- thence by wire Zb through the coil of the relay Rof line1, after which it branches, one branch being connected with the lowercontact-stop, r, of the armature R of the relay R, while the otherbranch is connected with the lower contactstop, 8, of the armature ofthe annunciator S, both branches of the circuit being normally open atthese contacts, as clearly shown in Fig. 2. The main line, which ismarked 1 in Fig. 2,, enters the multiple system of boards, and isdirectly connected, as shown at Y, Fig. 2, with all its terminal rings 0on all the boards, such as Y, other than its particular board. At boardX, however, where the operator is in special charge of this line, theline passes first through the coil of the annunciator magnet S, andthence to a point, t, where the circuit divides, one branch passing tothe ring-terminal c. The other branch is connected with the rear end ofthe armature S of the annunciator,

which is permanently connected by the wire a with the upper contact, R",of the relay-armature R. This armature, which is normally in contactwith its contact R as clearly shown in Fig. 2, is permanently connectedat its front end through a bar, 9, with the earth. The upper contact, U,of the annuuoiator-armature is connected with the operators instruments,as shown.

V is the ordinary aununciator dr0p. An 8 insulated contactplate, t, isarranged on the faces of-the boards near each terminal ring c, asclearly shown, and is connected, as shown, by the dotted line i with thelower contactstop, r, of the relay-armature R. Assuming now that a callis sent to the central office over line No. 1, the current will passthrough the coil of the magnet S of the annunciator, thence from thepointt by way of the end of the armature S, thence by wire 8 to the rearcontact, R of the relay-armature R, and through said armature and theground-bar r to earth. This current energizes the magnet S, causing itto attract its armature and let the annunciatordrop V fall, thusindicating that the call has been received. At the same moment thecontact of the armature S with its front lower 5 stop, 8, will completethe local circuit Z b from said contact through the armature S, line 8and relay-armature It, to ground. This com- 'pletion of the circuit willenergize the relayinagnet R, which attracts its armature R and I opensthe ground of the main line and local just traced at the contact R sothat the an nunciator-armature S will go to its upper front contact, U,and throw the operators instruments into the main line. The local Z bwill, however, be simultaneously closed through the contact-stop r,armature R, and contactstop 1", to ground.

The operator, upon being informed what line is wanted by the subscribercalling, will proceed first to test the terminal of that line toascertain whether it is in use or not, and this is done in the followingmanner: The

completion of the local circuit Z 11, as just described, causes acurrent of electricity to flow 2 through the coils O at both sections ofthe board X and Y. To ascertain, therefore, whether the line of anyparticular subscriber is in use, I use a pair of soft-iron plugs on theends, E, of each cord for connecting sub- 0 scribers. When this plug isinserted through the ring 0 into the hollow axis of the coil 0 at theterminal of the line to be tested, the plug becomes a core for theelectromagnetic coil, and is at once magnetized. If, therefore, the 3 5plug on the other end of the cord is touched to the plug in the terminalit will be attracted if there is any current flowing in the local, andthe operator will know that the line is in use. If the line wanted isnot in use, the op- 0 erator calls up the subscriber,as follows: He

touches one of the plugs E to an ordinary calling-battery bar, the useof which is well understood, and then touches the other plug to theinsulated contact t. This completes a cir- 4 5 cuit from thecalling-battery through the plugs and cord, contact t, wire 15, contactr of relay, coil of relay, and thence by wire Z I), through the variouscoils G of that line on the several boards to the local battery L B andground. The polarity of the calling-battery will be such as to coincidewith the local battery L B in causing a current to flow in this circuit.The relay-magnet of this particular line, at whatever board it may be,will therefore be energized and attract its armature B. This completesthe local circuit, as before traced, from the relay-coil R, contact 1",relay-armature R, and ground-plate r, to ground. The local circuit ofthe called line is therefore established in the same way as justdescribed, in connection with a calling subscriber. The action of therelay R will break the main line of the called subscriber at the contactR so that when the operator now plugs to the terminal of the line wantedand calls with his battery in the ordinary way, the annunciator-drop ofthat line at its particular board will not fall, and no confusion willtherefore arise. The two lines are connected in the ordinary way, andthe annunciator-drop V of the calling subscriber put up so as to connectthe opera tors telephone out of circuit. Of course, as it will beperceived, when two lines are connected for conversation, theannunciator-coil S of the calling subscriber will be included in theline between the two subscribers. When,therefore, they have finishedconversation, an impulse of electricity sent over the line by eithersubscriber in any ordinary way will cause the annunciator-armature todrop, thus throwing the operators telephones into the line again, and atthe same time by the falling of the drop indicating that they havefinished conversation. Before withdrawing the plugs from the respectiveterminals to disconnect the lines the rod 6, which moves endwise withinthe plug E in the calling subscribers terminal, is thrust forward bymeans of a lug, e, which projects from the side of the plug through anelongated slot therein. When the rod e is thrust forward, it breaks thelocal. circuit 1 b at a b, so that the relay R is demagnetized, and theapparatus in the line of the calling subscriber returns to its normalcondition. (Shown at X, Fig. 2.)

Under the arrangement shown the operator at any board can readilyascertain whether any line is in use. At the same time, by the use ofthe insulated contacts if placed in branches of the local circuits ofthe several lines, any subscriber may be called without danger ofcausing his annunciator to fall.

I claim as my invention- 1. The combination, in a multiple switchboard,of a main line, its terminal on each of the boards, an electric coil ateach of said terminals, a local circuit in which said coils areincluded,the annunciator S, and relay R, and electric circuits andconnections,substantially as set forth.

2. The combination, in a multiple switchboard, of the main line, itsterminals on the several boards, an electromagnetic coil at each too ofsaid terminals, a local circuit in which they are included, a movablecontact included in said, local circuit at each terminal, theannunciator S, and relay R, their circuits and connections, and aline-plug for making connections by means of which the local may bebroken at its movable contact when the line is to be disconnected fromthat of another subscriber.

3. The combination of the line terminalplate a, the electro-magnet coil,the local circuit in which said coil is included, the movable contact insaid localv circuit, and the plug formed with a movable slide or rod foropening the local circuit at said movable contact.

4. The combination of the main line, its terminals on the severalboards, an electro magnetic coil without a core at each of saidterminals, a local circuit in which it is included, and a pair of ironplugs, for the purpose set forth.

5. The combination of the several sections of board, a main line, ametallic terminal or ring for said line on each board, a directconnection between said terminals and the main line at each board exceptthe particular board to which the line belongs, an annnnciatormagnetplaced between the line and its terminal at its particular board, theoperators instruments which are thrown into the line by the fall of theannunciator-drop, and electric circuits and connections.

6. The combination of the several sections of board, a main line, itsterminals on the several boards, a local circuit for said line, thecoils in the local circuit at the several terminals of said line, theannunciator at the particular board of said line, a relay included insaid local circuit by means of which the ground of the main line isthrown off and the l ground of thelocal completed, an insulated Icontact arranged in proximity to each of said line terminals, and theelectrical connection between said contacts and the local circuit.

7. The combination of the several sections of board, the main line, itsseveral terminals, a local circuit which on its completion indicates atthe several terminals of said line that the line is in use, anannunciator for said line at its particular board, a relay also at saidboard by which the ground of the main line through the relay is thrownoff and the local circuit grounded when the relay is energized, aninsulated contact at each of said terminals, and the electricalconnection between said contacts and the local circuit, for the purposeset forth.

In testimony whereof I have hereunto subscribed my name.

THOMAS J. PERRIN.

Witnesses:

J AS. PosnY, WV. J. OLINE.

